According to a Major league official, the steep drop in offense in baseball has been primarily because of the ban on amphetamines and not on steroids.

This steep drop in offense is mainly due to efforts by Bud Selig & Co. for piggybacking the amphetamines ban on top of the steroids testing agreement with the union of players.

From NYdailynews.com:

But forget for the moment that there have only been 20 perfect games in history and only seven from 1900 to 1968, the year of the pitcher, after which major league poobahs elected to lower the mound from 15 inches to 10 to generate more offense. What we’re seeing in baseball this season is a dramatic decrease in offense. According to the Elias Bureau, runs per game are down from 9.3 last year to 8.95 and home runs per game are down to 1.87 - the first time since 1993 (the beginning of the steroids era) they’ve been below two per game.

And there’s more: As of Friday, the Atlanta Braves’ Martin Prado was leading the National League in batting with a .327 average and barely a dozen players in the NL were hitting over .300. In back-to-back games this week - shades of Juan Marichal and Warren Spahn dueling for 15 scoreless innings on July 2, 1963 - the Dodgers and Arizona Diamondbacks played scoreless ball into extra innings, with L.A. prevailing both times, 1-0, in 10 innings and 14. Then there was the Phillies getting shut out in three successive games by the Mets at Citi Field. Lastly, there’s the Colorado Rockies’ phenomenal Ubaldo Jimenez, who’s having a season comparable to Bob Gibson in 1968, when the St. Louis Cardinal Hall of Fame righty posted the lowest ERA (1.12) in 54 years, losing five 1-0 games along the way.

The wholeheartedly efforts by Bud Selig for preventing the relationship between baseball and steroids from reaching new heights and getting subdued for betterment of the game have been appreciated by many fans and baseball players of the past.